Electro Magnetic Compatibility (EMC) means the ability that a device or system runs with requirements met in an electromagnetic environment where the device or system is located, at the same time, no unbearable electromagnetic interference is happened to any other device in the environment where the device or system is located. With widely application of electronic products, a variety of electrical products used in everyday life are usually equipped with not only a motor but also several other electronic products such as an enclosed constant-speed three-phase asynchronous motor which is common in industry. Since the motor gives off electromagnetic wave during working, in order to stop the motor from giving off electromagnetic wave which may affect normal operation of the electronic products nearby, a motor equipped with an EMC element is usually required. The motor with the EMC component has little effect on the normal operation of the electronic products nearby, which brings convenience to the user and reduces production cost effectively. Furthermore, in order to stop electro-static discharge (ESD), the motor is normally further equipped with an ESD component as an over-voltage protection discharger.
The motor normally includes a conductive housing configured to provide an enclosed internal working environment for the motor and an insulating cover configured to contain several electronic components and prevent the electronic components from shorting out with the conductive housing and metal cover of the motor. The conductive housing is normally made of metal which structurally possesses protective property and grounding property in circuit. The insulating cover is normally made of plastics and configured to protect each of the electronic components from shorting out with each other and the conductive housing.
Normally, an EMC component and/or ESD component of the motor is located between the conductive housing and the insulating cover of the motor such that the EMC component and/or ESD component is directly contacted to the metal conductive housing of the motor so as to achieve grounding purpose. However, when the motor is working, the temperature thereof is very high, and the insulating cover is easy to be deformed in the heat. Furthermore, the hardness of the plastic material is insufficient; therefore, when the motor suffers severe vibration, the insulating cover will be deformed. All the deformations above may create a gap between the insulating cover and the conductive housing, which makes the contact between the EMC component and/or ESD component and the metal conductive housing insufficient or unstable, and the purpose of stable grounding cannot be achieved.